Best Practices while creating Stored Procedures

Stored Procedures in SQL Server provides lot of benefits compared to single/multiple adhoc SQL statements. They help in achieving consistent implementation of logic across applications and improve performance. They also provides us flexibility to design desired business rules and logic by combining various SQL statements, control flow IF-ELSE statements, WHILE loops, and other programming constructs.

Thus to design them requires a generic approach and some best practices that comes with experience as you work with them. I’m listing some of the best practices that must be followed everytime you create Stored Procedures:

2. PARAMETER SNIFFING: Do not use SP parameters directly within the WHERE clause of SQL statements. This may cause the case of Prameter Sniffing. To avod this assign the parameter values to local variables and then use them with SQL queries.

3. Use table variables: Try to use table variables instead of temporary tables inside the SP to cache small record sets whenever possible.

4. Use of Temp Tables: If you think that the temporary record set may exceed upto millions of rows, then try using temporary table instead of table variables. Also try creating indexes on temporary tables if required.

5. Avoid using CURSORS: This will make your SP slow and degrade the performance. Try using more effecient SET based approaches instead of using CURSORS.

7. Using Transactions: Use Transactions by using BEGIN TRANSACTION and COMMIT/ROLLBACK TRANSACTION blocks to make sure that your actions follow ACID properties.
But keep the transctions as short as possible to create less blocking in database and thus avoiding deadlocks.

8. Aliasing objects: Do not use SQL Server reserve keywords while naming SQL Server objects, like for: tables, columns, views, etc. Although it allows most of the time, but its better to use other and better naming conventions.

9. Avoid GOTO stmt: Do not use GOTO statements in your code as it is considered a bad programming practice (and in every other programming language). Try comming up with a better approach/logic, use conditional IF-ELSE logic, WHILE loops and other programming constructs.

10. Avoid ‘sp_’ prefix : Do not prefix the SP name with ‘sp_’. If it begins with ‘sp_’ then the compiler will first search it in master database and then in the current one, thus delaying the execution.

11. Use fully qualified objects name: in your SQL queries, this helps in quickly finding the cached/compiled plan. Also execute the SP by using its fully qualified name, like: EXEC dbo.SPname

12. Use WITH ENCRYPTION: You can also use ‘WITH ENCRYPTION’ option while creating SP to hide the code.

13. Add Comments: Try to put comments wherever possible to give details and idea to other developers what actually your code is doing.

14. Use BEGIN-END code block: Try to bind your whole SP code within BEGIN-END block. Although it is optional but it looks good and gives a better picture.

16. Beautify your code: Well indent your code by uisng TABs, Spaces and New line (ENTER). Try going vertically downwards with your code rather expanding horizontally. This will make your code easy to read and more understandable to other developers.

First of all Stored Procedures are not pre-compiled, when you create them they are just parsed and created as a simple DB object. Theyare compiled first time when that are executed for the first time, the plan is created and on further execution this plan is created until they re-compiles again, due some factors.

Secondly, as mentioned above one should not use “sp_” prefix while naming SPs, because while execution SQL Server will search this SP on master DB then on the current DB, thus delaying the executing time.